The present invention relates to time and timezone information in Intelligent Networks (IN). More particularly, and not by way of limitation, the present invention is directed to a system and method for calculating a local subscriber's local time more accurately.
Several operators of mobile telephony systems have or plan to introduce peak/off-peak hours for real-time rating of prepaid calls. For GSM network solutions based on the Customized Applications for Mobile network Enhanced Logic (CAMEL) Application Part (CAP), there is a deficiency that can prevent accurately obtaining a subscriber's local time.
Existing real-time solutions requiring the time at the subscriber's locale rely on the time reported to the Service Capability Point (SCP) in a GSM network. The time and time zone information reported in a CAP Initial Data Point (IDP) message is used to calculate whether peak or off-peak hours are in effect. Details of CAMEL can be found in the reference “GSM 02.78: “Digital cellular telecommunications system (Phase 2+); Customised Applications for Mobile network Enhanced Logic (CAMEL Phase 2)—stage 2”.
Existing CAMEL based solutions rely on the time and time zone information conveyed in the CAP IDP message to calculate and record the subscriber's calling/called time. However, this time is based on either the serving Mobile Switching Center's (MSC's) location for Mobile Originated (MO) calls or the Gateway MSC's (GMSCs) location for Mobile Terminated MT calls.
In the case of an MO call, it's possible that a cell site serving the subscriber is located in either a different time zone and/or in a time zone that has different rules for the observance of Daylight Saving Time (DST) than the serving MSC. Typically, in the United States (US), this discrepancy could be plus or minus one hour depending on location.
For an MT call where the subscriber is roaming, the discrepancy can be even greater. For example, if a subscriber's GMSC is located on the eastern coast of the US, but the subscriber is roaming on the western coast, the time reported to the SCP could be off by three hours.
These discrepancies can lead to customer confusion, off-peak hours expanded to cover many time zones, increased calls into customer service centers and awards of free calls to prevent customer dissatisfaction. It would be advantageous to have a system and method for providing a more accurate indication of the subscriber's local time that overcomes the disadvantages of the prior art. The present invention provides such a system and method.